Surgical instrument positioning system

ABSTRACT

A percutaneous tissue removal apparatus having a flexible drill shaft, a cutting tip mounted on the shaft a power source for transmitting motion to the shaft to move the cutting tip against tissue and a suction source for removing tissue fragments along the shaft to a location outside the tissue mass while cutting. The apparatus may include a container for collecting one or more selected components of the harvested tissue fragments for implantation of the fragments preferably into the body of the patient from whom they were removed. Where the tissue to be cut is bone, a cutting tip is preferably made of a polymeric material which is softer than the cortical portion of the bone, although the cutting tip may be made of a ceramic or a composite material. A second flexible shaft may be provided either within or about the flexible drill shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/483,676, filed Jan. 14, 2000 now U.S. Pat. No. 6,468,289 which inturn is a continuation of U.S. patent application Ser. No. 09/323,326,filed Jun. 1, 1999 (now U.S. Pat. No. 6,174,313 B1). The aforementionedapplication Ser. No. 09/323,326 is itself a continuation of U.S. patentapplication Ser. No. 08/834,835, filed Apr. 11, 1997 (now U.S. Pat. No.5,935,131). The aforementioned application Ser. No. 08/834,835 is itselfa divisional of U.S. patent application Ser. No. 08/695,274, filed Aug.9, 1996 (now U.S. Pat. No. 5,694,951). The aforementioned applicationSer. No. 08/695,274 is itself a divisional of U.S. patent applicationSer. No. 08/353,494, filed Dec. 9, 1994 (now U.S. Pat. No. 5,577,517).The aforementioned application Ser. No. 08/353,494 is itself adivisional of U.S. patent application Ser. No. 08/134,914, filed Oct.12, 1993 (now U.S. Pat. No. 5,403,317). The aforementioned applicationSer. No. 08/134,914 is itself a divisional of U.S. patent applicationSer. No. 07/545,908, filed Jun. 28, 1990 (now U.S. Pat. No. 5,269,785).

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to the field of tissue removal and tissuegrafting. More particularly, the present invention relates to anapparatus and method for the percutaneous cutting and removal ofselected portions of tissue from a patient and the possible harvestingand implantation of the tissue portion in the donor.

2. Description of the Prior Art

There are various known methods and apparatus for the cutting andremoval of tissue fragments from a human. Each of these, however,suffers from one or more deficiencies.

U.S. Pat. No. 4,832,683 shows an instrument for ultrasonic cutting ofbones, with irrigation or suction. However, there is no suction whilecutting, no removal of the cut bone or tissue, and no flexibility in theinstrument.

U.S. Pat. No. 4,265,231 shows apparatus for drilling a curved holehaving a flexible shaft confined in a rigid tubular sheath, but whichshows no removal of cut bone or tissue.

U.S. Pat. No. 4,541,423 shows apparatus for drilling a curved holehaving a flexible shaft confined in a semi-rigid tubular sheath, butwhich shows no removal of cut bone or tissue.

U.S. Pat. No. 4,589,414 shows a surgical cutting instrument with areciprocatory cutting motion, but which has no removal of cut bone ortissue, and no flexibility in the instrument.

U.S. Pat. No. 4,603,694 shows a rotating arthroscopic shaver withsuction, but which is not flexible and which has no removal of cut boneor tissue.

U.S. Pat. No. 4,751,922 shows a flexible medullary reamer with a plasticshaft and a guide rod, but which has no suction and no removal of thecut bone or tissue.

U.S. Pat. Nos. 4,798,213, 4,649,918, and 4,142,517 show variousapparatus for bone coring.

SUMMARY OF THE INVENTION

The present invention is a percutaneous tissue removal apparatusincluding a flexible drill shaft and means for transmitting motion tothe shaft. A cutting tip is mounted on the shaft to cut tissue fragmentsfrom the tissue. The tissue fragments are removed by suction along theflexible drill shaft to a location outside the body while cutting. Oneor more selected components of the removed tissue fragments may becollected for implantation, preferably into the body of the patient fromwhom they were removed. Because the drill shaft is flexible, the surgeoncan guide the cutting tip into various locations within the tissue froma small (percutaneous) incision. The surgeon can cut around arcs orangles, rather than only being able to go in a straight line, to reachany desired location, and to avoid vital tissue which would otherwise bein the cutting path. For example, when removing unwanted tissue inside aknee joint the drill shaft can deform, and is therefore less likely todamage normal tissue or joint surfaces. None of these functions ispossible with a straight line system.

GENERAL DESCRIPTION OF THE INVENTION

The present invention is a percutaneous tissue removal device andmethod. In the preferred embodiments described below, the apparatus andmethod are illustrated as used for removal of bone tissue, but suchdescription is for illustrative purposes only. The invention is notlimited to the removal of bone tissue and may be used for removal ofcartilage, muscle, fetal tissue, etc. It may be used to break up andremove kidney stones, in the gall bladder for a stone or tumor, in thestomach, in the colon to remove a polyp or tumor, etc. It can reachspaces not currently available with the straight line systems currentlyavailable.

A percutaneous tissue removal apparatus in accordance with the presentinvention includes a flexible drill shaft for insertion inside a tissue.A cutting tip is mounted on the drill shaft for cutting the tissue.Either rotating motion or reciprocating motion is transmitted to thedrill shaft to move the cutting tip against the tissue to cut tissuefragments from the tissue. While cutting, the tissue fragments areremoved by suction to a location outside the body. The drill shaft andcutting tip are small enough to be usable percutaneously. They may alsobe used for endoscopic, arthroscopic or fiberoptic or open surgery.

Because the drill shaft is flexible, the surgeon can guide the cuttingtip into various locations within the tissue from one percutaneousincision. The surgeon can cut around arcs or angles, rather than onlybeing able to go in a straight line, to reach any desired location, andto avoid vital tissue which would otherwise be in the cutting path. Theflexible drill shaft also allows the surgeon when working inside a bone,for example, to keep the cutting tip away from the harder outer corticalbone and to remove only the softer inner cancellous bone. None of thesefeatures is available with the current straight line cutting devices.

The drill shaft may be made of metal, of polymeric material to reducefriction, or of a composite material. Extensive use of polymers in thedrill shaft, its housing if provided, and the cutting tip area reducesfriction substantially, thus requiring less energy and generating lessheat within the tissue. The drill shaft is drivable by hand (forimproved feel) or by motor, at variable speeds based on the need for thetissue removed.

To provide for the collection of the tissue fragments to be harvested,the removal apparatus has an axially extending suction passage along thedrill shaft through which the tissue fragments are removed. The suctionpassage has a smooth lining to keep the tissue fragments or graftmaterial contained and to reduce friction of the harvested tissuefragments. This lining may be the inside diameter of the flexible drillshaft itself, or may be a separate liner sleeve which can be removed anddisposed of when it becomes unsanitary or clogged, without having toremove the drill shaft and cutting tip. Alternatively, if a separateguide sleeve or guide rod is used the suction passage may be formedbetween the drill shaft and the guide sleeve or guide rod. In such acase, the drill shaft may be solid rather than hollow.

The cutting tip is made of a material which is harder than the materialto be cut. The cutting tip may be slightly larger in diameter than thedrill shaft. The cutting tip may be made of a polymeric material or acomposite material. Alternatively, the cutting tip may be made of aceramic material. The cutting tip is separable from the drill shaft, andseveral different cutting tips may be provided in varying hardnesses, sothat the surgeon can selectively remove various portions of tissue asdesired.

By virtue of its flexibility, the flexible drill shaft, when removingbone tissue, may stay within the cortical confines of the bone.Alternatively, it may work with a guide device to control the locationof the cutting tip within the bone. The guide means may be a guide rodextending within the flexible drill shaft, or a hollow guide sleeveoutside the flexible drill shaft. The guide rod or guide sleeve may berigid in a particular shape, to fit a particular application; or it maybe bendable into a particular shape which it will hold; or it may beselectively rigidifiable into a particular shape in situ. The guidemeans may include structure for positioning the tip of the flexibledrill shaft. The guide means may also be inserted into a separateflexible tube system to guide it to a specific location, then removed,allowing the flexible drill to be inserted.

Fluid may be injected through the flexible drill shaft to a locationadjacent the cutting tip to increase the efficiency of the tissueremoval and to limit thermal necrosis. Alternatively, a fluid injectionpassage may extend axially along the flexible drill shaft, the drillshaft. Alternatively, fluid may be injected through the suction passage,alternating with the suction. The fluid injection may be constant or itmay be pulsatile in nature. If fluid injection is used, centrifuging ofthe harvested material may be performed.

Means for collecting one or more selected components of the harvestedtissue fragments may include a known trap or filter connected to theoutlet of the suction passage. Removed tissue may be centrifuged toseparate its components. Thus, the tissue fragments are not merelyremoved from the body and may be harvested for implantation of thefragments, preferably into the body of the patient from whom they wereremoved. In order to maintain the sterility of the tissue removed, theentire suction apparatus including the suction passage and the trap orfilter is sterilized, and, if necessary, is disposable.

With the present invention all work is done by going percutaneouslythrough the skin to a specific tissue area to minimize the damage toskin, muscle, and bone. For example, when removing bone tissue, traumais limited to a small opening in the hard outer structural corticalbone, limiting postoperative bleeding from the bone which is difficultto stop, because the small operative hole can easily be plugged afterthe grafting procedure is completed, preventing postoperative bleedinginto soft tissue. There is only intraosseous bleeding, so that fewercomplications, and less pain, are likely to arise. The operation doesnot create stress risers which would weaken the bone. Thus, the presentinvention provides a safe and efficient way to collect and reuse apatient's own tissue.

Human tissue grafting works best using the patient's own tissue as donormaterial. Therefore, the harvested tissue may be implanted in thedonor's own body for grafting. To implant one or more selectedcomponents of harvested bone fragments, for example, a cannula isinserted through the skin and muscle to the area of the bone where thegraft is to be placed. A drill or curette is then used to remove aportion of the outer cortical bone. A curette or probe is insertedthrough the cannula to clear out the area where the graft is to beplaced, either in open surgery or through X-ray guidance in percutaneoussurgery. The harvested tissue fragments may be packed or compressed intoa plug of tissue graft material, of a specific shape, with or withoutblood or fibrin for adhesion. Or, a retaining material such as abiodegradable mesh may be used to hold the graft material together as aunit. The graft material and its retaining material are then inserted atthe graft location in the bone. Alternatively, the graft material isinserted and then sealed in place with a mass of formable polymericmaterial inserted over the graft material to hold the graft together inposition.

A method of percutaneous tissue removal in accordance with the presentinvention includes the steps of placing within a tissue mass a flexibledrill shaft having mounted thereon a cutting tip for cutting the tissue;transmitting motion to the drill shaft to move the cutting tip againstthe tissue to cut tissue fragments from the tissue; and removing thetissue fragments by suction to a location outside the tissue mass whilecutting the tissue. The method may further include the step ofcontrolling the location of the cutting tip within the tissue with aguide rod, the step of collecting one or more selected components of theharvested tissue fragments, and/or the step of implanting the fragmentsinto the body of the patient from whom they were removed.

BRIEF DESCRIPTION OF THE INVENTION

Further features of the present invention will become apparent to thoseskilled in the art to which the present invention relates from readingthe following specification with reference to the accompanying drawings,in which:

FIG. 1 is a schematic view of a tissue removal system in accordance withthe present invention and including a flexible drill;

FIG. 2 is a schematic view of a hand-powered flexible drill for use inthe system of FIG. 1;

FIG. 3 is a schematic view of a portion of a hollow flexible drive shaftfor the flexible drill;

FIG. 4 is a schematic view similar to FIG. 3 and showing a guide rodinside the hollow flexible drive shaft;

FIG. 5 illustrates a portion of a flexible drill including a hollowflexible inner cutting shaft within a flexible outer sleeve and asuction passage between the two shafts;

FIG. 6 is a view similar to FIG. 5 with a suction passage within theinner shaft;

FIG. 7 illustrates a portion of a flexible drill including a solidflexible inner cutting shaft within a flexible outer sleeve and asuction passage between the two shafts;

FIG. 8 illustrates a portion of a flexible drill including a solidformable inner guide rod within a flexible outer cutting sleeve and asuction passage between;

FIG. 9 illustrates a portion of a flexible drill including a hollowflexible inner cutting shaft within a solid formable outer sleeve and asuction passage between;

FIG. 10 is a view similar to FIG. 9 with a suction passage within theinner shaft;

FIG. 11 illustrates a portion of a flexible drill including a solidflexible inner cutting shaft within a solid formable outer sleeve and asuction passage between;

FIG. 12 illustrates a portion of a flexible drill including a relativelyflexible portion between two relatively rigid portions;

FIG. 13 illustrates the use of a liner sleeve in a suction passage;

FIG. 14 is a view illustrating a number of different cutting tips usablewith the flexible drill;

FIGS. 15 and 16 are schematic views illustrating the provision of aplurality-y of separately inflatable bladders as a guide mechanism for aflexible structure and the operation of a guidance system for locatingthe tip of the flexible structure;

FIGS. 17A and 17B are schematic views illustrating the forming ofharvested tissue fragments into a compressed plug suitable forimplantation;

FIG. 18 is a schematic view illustrating the implantation of harvestedbone fragments using a polymeric mesh as a retainer; and

FIGS. 19A and 19B are schematic views illustrating the implantation ofharvested tissue fragments using a formable polymeric sealant as aretainer.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is described herein with reference to apercutaneous bone removal and harvesting apparatus and method. It shouldbe understood that the present invention is not limited to the removalof bone tissue, but is useful in the removal of any hard or soft tissuein the body such as excess, unwanted, or tumorous tissue or tissue usedfor reimplantation or grafting.

A percutaneous bone removal apparatus 10 (FIG. 1) in accordance with thepresent invention includes a flexible drill 12. The flexible drill 12has a flexible shaft 14 and a cutting tip 16 at the distal end of theshaft 14. The proximal end of the flexible shaft 14 is connected by ahousing 18 to a motor or other power source 20 to provide rotationalmotion or reciprocating motion in a manner known in the art.Alternatively, the drill 12 may have an angled drive, such as 90 degreedrive or any angle, with the motor drive connected at an angle to thelongitudinal extent of the suction and cutting apparatus.

Control means indicated schematically at 21 may include one or moreswitches or valves to turn on or off the suction, irrigation, and motordrive control. A fluid injection source 22 is connected by a fluidinjection line 24 to the housing 18 of the flexible drill 12. A suctionsource 26 acts through a trap or filter or strainer 28 and a suctionline 30 to provide suction capabilities for the flexible drill 12.

FIG. 2 illustrates a flexible drill 12 a in which the housing 18 a isconnected to a hand controller 20 a. The hand controller 20 a allows thesurgeon to operate the flexible drill 12 a by hand, imparting eitherrotational or reciprocating movement to the flexible shaft 14 a andcutting tip 16 a.

FIG. 3 illustrates a portion of a basic version of a flexible drillhaving a cutting tip 16 mounted on a flexible drive shaft 31. The driveshaft 31 has an outer surface 32 and an inner surface 34 defining alongitudinally extending suction passage 36. The cutting tip 16 has acutting edge 40 and an opening 38 through which tissue fragments cut bythe cutting tip 16 may be aspirated. The tissue fragments are drawnthrough the suction passage 36 in the flexible drive shaft 31 and thenceinto the suction line 30 (FIG. 1) for collection in the trap or filteror strainer 28.

FIG. 4 illustrates the use of a pre-inserted guide rod 42 with aflexible drill of the present invention. The guide rod 42 extendsthrough the suction passage 36 of the flexible drive shaft 31. The guiderod 42 may be any suitable structure including a K-wire or other knowndevice. The cutting tip 16 may have a centrally located opening in itsdistal end to allow insertion of the flexible drill over the guide rod42. The guide rod 42 is first placed in the body, then the flexibledrill is inserted over the guide rod 42 and guided to the location fromwhich tissue is to be harvested.

FIG. 5 illustrates an embodiment of a flexible drill having an outersleeve 44 circumscribing a flexible drill shaft 41. The flexible outersleeve 44 may be formed of a metal or composite material or may beformed of a polymeric material which may be the same as or differentfrom the material of the flexible inner cutting shaft 31. The outersleeve 44 is fixed (non-moving) to minimize tissue damage. A suctionpassage 46 is defined between the outer surface of the flexible innershaft 31 to which the cutting tip is attached, and the inner surface ofthe flexible outer sleeve 44. Alternatively, as shown in FIG. 6, asuction passage 48 may be defined within the flexible inner cuttingshaft 50. In this case, the outer surface of the flexible inner shaft 50is preferably, as illustrated in FIG. 6, in close proximity to the innersurface of the outer sleeve 44 to increase stability. The use ofpolymeric materials for both the inner shaft 50 and the outer sleeve 44provides for reduced friction between the sleeve 44 and the shaft 50 forease of operation and reduced heat generation.

FIG. 7 illustrates an alternate embodiment of the apparatus of FIG. 5 inwhich the flexible inner cutting shaft 52 is formed as a solid shaftrather than a hollow shaft. The harvested tissue fragments travelthrough the suction passage 46 between the inner shaft 52 and the outersleeve 44.

FIG. 8 illustrates apparatus similar to FIG. 7 in which a fixed(non-moving) inner shaft 54 is made of a solid, formable, material andthe cutting tip is mounted oh a flexible rotating outer sleeve 56.Suction is drawn through a suction passage 58 between the shaft 54 andthe sleeve 56. The inner shaft 54 is made from a semi-rigid materialwhich is bendable to a desired curvature, at the use site, to select thecurvature of the hole to be drilled, and which is rigid enough to retainthat curvature in use while the drill shaft 56 rotates around it. Suchmaterial is disclosed in U.S. Pat. No. 4,541,423, the disclosure ofwhich is incorporated herein by reference.

FIGS. 9, 10 and 11 illustrate embodiments of the flexible drill of thepresent invention in which a flexible inner cutting shaft, which may behollow or solid, is disposed within a non-moving formable outer sleeve.The formable outer sleeve 60 is made of a semi-rigid bendable shaperetaining material as described above with reference to FIG. 8. In FIG.9, a hollow flexible inner cutting shaft 62 is disposed within the outersleeve 60 and defines therebetween a suction passage 64. In FIG. 10, ahollow flexible inner cutting shaft 66 is disposed in close proximity toand within the outer sleeve 60, with a suction passage 68 formed withinthe flexible inner cutting shaft 66. In FIG. 11, a solid flexible innercutting shaft 70 is disposed within the outer sleeve 60, definingtherebetween a suction passage 72.

FIG. 12 illustrates a portion of a flexible drill shaft 80 in accordancewith the present invention in which a pair of relatively rigid drillportions 82 and 84 are joined by a relatively flexible drill portion 86.The relatively rigid drill portion 82 includes an outer sleeve 88, aninner shaft 90, and a suction passage 92 therebetween. The relativelyrigid drill portion 84 includes an outer sleeve 94 like the outer sleeve88, an inner shaft 96 like the inner shaft 90, and a suction passage 98therebetween. The drill portion 86 includes a relatively flexible innershaft portion 100 disposed within a relatively flexible outer sleeveportion 102, defining therebetween a suction passage 104. The relativelyflexible inner shaft portion 100 connects the relatively rigid innershaft portions 90 and 96. The relatively flexible outer sleeve portion102 connects the relatively rigid outer sleeve portions 88 and 94. Thesuction passage 104 in the relatively flexible drill shaft portion 86connects the suction passages 92 and 98. Either the inner shaft or theouter sleeve of the flexible drill 80 may have a cutting tip mountedthereon. Thus, with a flexible drill shaft made in this manner, it isnot necessary that the entire drill shaft be made of flexible materials,but rather “joints” such as are formed by the relatively flexibleportion 86 may be placed along the longitudinal extent of a relativelyrigid drill shaft as desired.

FIG. 13 illustrates how a disposable single-use liner sleeve 110 may beused in a flexible drill of the present invention. The liner sleeve 110shown in FIG. 13 is located within an outer sleeve 112 and is shownabout a guide rod or guide wire 114. Suction is drawn through a passage116 within the liner sleeve 110. The disposable single-use liner sleeve110 provides an absolutely sterile environment through which harvestedtissue fragments may pass. The inner surface 118 of the liner sleeve 110is extremely smooth in order to facilitate passage of the harvestedtissue fragments therethrough. It should be understood that a linersleeve like the liner sleeve 110 may be used with any suitable flexibledrill shaft configuration in accordance with the present invention, andnot merely with the configuration shown in FIG. 13.

FIG. 14 illustrates several different cutting tips which may be attachedin a known manner to a flexible drill shaft in accordance with thepresent invention. The technology for the cutting tips is not specificto the present invention, but rather the cutting tips may be designed inaccordance with known principles.

The cutting tip 120 (FIG. 14) has a cutting edge 122 at least partiallydefining an opening 123 through which suction is drawn. The cutting tip124 includes a plurality of cutting edges 126 defining a plurality ofsuction openings 128 disposed along the outer circumferential portion ofthe cutting tip 124. The cutting tip 130 is similar to the cutting tip124 but includes cutting edges 126 a and suction openings 128 a whichextend to the end of the cutting tip 130. Furthermore, the cutting tip130 is blunt rather than sharp, to avoid perforation of tissue, such asbones.

The cutting tip 132 has a spiral cutting edge 134 defining a spiralsuction opening 136. The cutting tip 138 has at least one longitudinallyextending cutting edge 140 at least partially defining a longitudinallyextending suction opening 142. The cutting tip 143 is formed as a burrwith fluted cutting edges 144 and suction openings 145, and isespecially suited for shaving operations such as removal of bone spurs,etc. The cutting tip 146 has twin cutting edges 147 and 148 and asuction opening 149. The cutting edges 157 and 148 can be configuredwith the leading edge to grab the tissue and the trailing edge to cutthe tissue.

The configuration of a cutting tip for use in accordance with thepresent invention is a design choice within the skill of the art. Thegoals to be met are proper cutting and suction capabilities,controllability and shape so as to avoid unwanted damage to areas oftissue not to be cut. For example, when removing the softer cancellousportion of bone, the cutting tip may be made of a material which isharder than the cancellous material of the bone but softer than thecortical portion of the bone to avoid damage thereto. Metal may beuseful, and suitable polymers are also readily available. Ceramicmaterials and composites are also suitable. Also, the cutting tip may bearranged as a rotating flexible shaft within a fixed flexible outershaft, with a cutting edge on the rotating shaft to cut tissue offagainst the fixed edge. In such a case, the apparatus may beadvantageously configured with one shaft being metal and the otherpolymeric, to minimize friction and heat buildup.

FIGS. 15 and 16 illustrate an alternate guidance system for positioninga flexible drill shaft 152 and its associated cutting tip. Disposedwithin the sleeve 150 is a guidance mechanism 152 including a pluralityof inflatable elements spaced serially. The inflatable elements, wheninflated, rigidify and become straight, while when in the deflatedcondition they are soft and flexible and may be curved or bent. Thus, asseen in FIG. 15, both the inflatable elements designated 154 and theinflatable elements 156 are curved. In FIG. 16, the inflatable elements154 have rigidified and straightened, while the inflatable elements 156remain in their curved position. The inflatable elements may also beaccordion shaped, expanding in length as they are inflated. Themechanism 152 may be augmented with a known cable guidance system.

By selectively and individually controlling the rigidification of any orall of the inflatable elements of the mechanism 152, the inflatablemechanism 152 and its associated outer sleeve 150 may be selectivelyformed into almost any desired shape or position. Suitable control andvalving apparatus is provided for controlling the inflation of theinflatable elements. Such apparatus may be, when only a few elements arepresent, a simple mechanical valving apparatus. When more elements arepresent, or more sophisticated or complex control thereof is desired, amicroprocessor may be used to control the inflation of each segment.Separate inflation and deflation lines can be used, or one line can, byalternating valving, serve both functions. In such case, the controlsignals may be multiplexed down the structure via electric wire, opticalfiber, or radio control, for example.

At the distal end of the mechanism 152 is a tip guidance mechanism 160including a plurality of inflatable members 162. The inflatable members162 when in a deflated condition are flexible and relatively straight.When inflated, as shown in FIG. 16, the members 162 assume a preformedshape which may be curved or straight and which is illustrated herein asa curved shape, bending radially outwardly to engage the surface ofadjacent tissue 164 and curve the end of the device into an appropriateposition. The members 162 may be constructed, using known principles, toassume any desired shape. By controlling the positioning of one or moreof the elements 162, the tip portion 168 of the guidance mechanism 152may be selectively placed in any position relative to the tissue 164,thus positioning the end of the sleeve 150. The air bladder guidancesystem as described may be used in conjunction with a flexible tubeseparate from the flexible drill shaft, order to guide the flexible tubeto a specific location and position it there, thereafter removing theguidance system and allowing a flexible drill to be inserted.

Means for collecting one or more selected components of the harvestedtissue fragments includes a mechanism 28 (FIG. 1) which may be a knowntrap or filter connected to the outlet of the suction passage 30.Removed tissue may also be centrifuged if necessary or desired, keepingthe components such as bone, cells, and blood and discarding fluid.These components and connections, and their uses, are well known in theart and thus are not described herein in greater detail. The harvestedtissue fragments are not merely removed from the body of the patient,but are also collected in the structure 28 and thus harvested or savedfor later implantation of the fragments, preferably into the body of thepatient from whom they were removed. Such harvesting and implantationare desirable because human tissue grafting works best using thepatient's own tissue as donor material.

In preparing the harvested graft material for implantation, the tissuefragments alone are spun or compressed (see FIG. 17B) to form them intothe desired shape. When the tissue is harvested, blood and blood clotsare often drawn along with the tissue fragments. The blood componentfibrin is a sticky clotting component, and can be used to aid in holdingthe tissue fragments together for implantation. Thus, the blood can beis separated from the tissue fragments and then spun to separate thefibrin for use with the tissue fragments. Alternatively, the entire massof tissue fragments and blood is compressed into a specific shape toform the mass into a specific, appropriate shape for implantation intothe body.

The surgeon can also place other substances into the graft material tobe implanted, such as other tissue graft material, collagen,antibiotics, or ceramic hydroxyapatite or tricalcium phosphate to aid inbone ingrowth. In such a case, when the blood or fibrin is used also,the graft has the adhesive qualities of the blood or fibrin and thebiological properties of the bone (or other) tissue, along with theappropriate medical properties of any other material included.

Harvested tissue fragments before implantation are preferably packed orcompressed into a plug of tissue graft material. Alternatively, thetissue fragments may be left in a more loose state, or only certainselected cells, components, or tissue fragments are used. Any suitablemeans of packing or compressing fragments may be used. FIGS. 17A and 17Billustrate schematically a simple apparatus for doing so. As viewed inFIGS. 17A and 17B, the harvested tissue pieces 170 are placed into aform or mold 172 and then compressed by a movable compressor 174 to forma plug 176 of a desired shape or size. Unwanted fluid drains out throughone or more fluid outlets 178, while the graft, cells, fibrin, and bloodclot tissues remain within the form 172.

To implant one or more selected components of the harvested tissuefragments, for example in grafting bone tissue onto a bone, a cannula180 is inserted through the skin 182 and muscle 184 to the area of thebone 186 where the graft is to be placed. A curette or probe is theninserted through the cannula 182 to clear out the area 188 where thegraft is to be placed.

The harvested tissue fragments are compacted or compressed into a plug190 of tissue graft material. A retaining material such as a knownbiodegradable or other polymeric mesh 192 is then used to hold the graftmaterial 190 together as a unit. The retaining material may also be asac of biodegradable material used to hold the graft material. The saccan be closed by a clamp or by crimping or heat sealing. The graftmaterial 190 and its retaining material 192 are then inserted into thegraft area of the bone. The cannula 180 may then be removed.Alternatively, the tissue graft material may be held in place by a massof biodegradable or other polymeric material used as a sealant for theopening in the bone 186. The graft material can be compressed or spuninto a specific shape. Thus, if an implant is needed to fit a specificshape of bone defect, the graft material can be formed in the shapeneeded and packed directly into the bone gap.

The bone graft material may also be implanted in the loose condition asdescribed above. The bone graft material 194, if loose, can be insertedthrough a funnel 196 and a sleeve 198 located within the cannula 180 tothe area 188 to be grafted. It is then packed in place as desired usinga suitable instrument. Next, an injector 200 is used to inject a mass offlowable biodegradable or other polymeric material 202 for use as asealant to seal the bone graft material 194 in position. The use of aflowable biodegradable material is preferable in that it allows thesurgeon to form in situ a custom shaped sealant plug to seal the openingin the tissue graft area, which will eventually resorb as new tissuegrows into its place.

The apparatus may include, as noted above, fluid injection means 22 and24 for injecting fluid through the flexible drill to a location adjacentthe cutting tip to aid in cutting and removal of the harvested tissuefragments. For example, in the drill shaft structure illustrated in FIG.5, fluid may be injected through a fluid injection passage 204 withinthe flexible inner cutting shaft 31, while suction is drawn in theopposite direction through the suction passage 46. Alternatively, thesuction may be intermittently discontinued and fluid may be injectedthrough the suction passage, alternating with the suction. The fluidinjection may be constant or it may be pulsatile in nature.

The present invention thus provides a method of percutaneous tissueremoval which includes the steps of placing adjacent to a tissue mass aflexible drill shaft 14 having mounted thereon a cutting tip 16 forcutting the tissue; transmitting motion to the drill shaft 14 to movethe cutting tip 16 against the tissue to cut tissue fragments from thetissue; and removing the tissue fragments by suction to a locationoutside the tissue mass while cutting the tissue. The method may furtherinclude the step of controlling the location of the cutting tip withinthe tissue with a guide mechanism, the step of collecting one or moreselected components of the harvested tissue fragments, and/or the stepof implanting the fragments into the body of the patient from whom theywere removed.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes and modifications within the skill of the art areintended to be covered by the appended claims.

What is claimed is:
 1. A surgical instrument positioning systemcomprising: an elongate member having proximal and distal ends; and atip positioning mechanism located at the distal end of the elongatemember, wherein the tip positioning mechanism includes a plurality ofinflatable members.
 2. The surgical instrument positioning system ofclaim 1 further comprising a sleeve having a lumen configured anddimensioned to receive at least a portion of the elongate member.
 3. Thesurgical instrument positioning system of claim 2 wherein the elongatemember includes a plurality of inflatable elements.
 4. The surgicalinstrument positioning system of claim 3 wherein the inflatable elementsare substantially accordion shaped and expand in length when inflated.5. The surgical instrument positioning system of claim 2 furthercomprising valving means for selectively inflating a number of theplurality of inflatable elements so that the elongate member assumes apredetermined shape.
 6. The surgical instrument positioning system ofclaim 5 further comprising a microprocessor to control the valvingmeans.
 7. The surgical instrument positioning system of claim 5 whereincontrol signals control the selective inflation.
 8. The surgicalinstrument positioning system of claim 7 wherein the control signals aretransmitted by electrical wire, optical fiber, or radio waves.
 9. Thesurgical instrument positioning system of claim 1 wherein the inflatablemembers are flexible and substantially straight when deflated and assumea preformed shape to engage a surface of tissue when inflated.
 10. Thesurgical positioning system of claim 9 wherein at least one of theinflatable members bends radially outward.
 11. A surgical instrumentpositioning system for positioning a surgical instrument having a sleevewith proximal and distal ends, the system comprising: a plurality ofpositioning elements extending along the sleeve, with each of theplurality of positioning elements selectively actuatable to eitherstraighten or bend the respective positioning element; and a controlmechanism for controlling the actuation of at least one of the pluralityof positioning elements, wherein actuation of at least one of theplurality of positioning elements flexes the sleeve to assume anon-linear shape.
 12. The surgical instrument positioning system ofclaim 11 wherein the system is a part of the surgical instrument. 13.The surgical instrument positioning system of claim 12 wherein thecontrol mechanism is located on the proximal end of the sleeve.
 14. Thesurgical instrument positioning system of claim 13 wherein the pluralityof positioning elements are disposed within the sleeve.
 15. The surgicalinstrument positioning system of claim 14 wherein the plurality ofpositioning elements are spaced serially with respect to each other. 16.The surgical instrument positioning system of claim 15 wherein each ofthe plurality of positioning elements is an inflatable element, each ofthe inflatable elements flexible in an uninflated state and rigid in aninflated state.
 17. The surgical instrument positioning system of claim16 wherein the inflatable elements are substantially accordion shapedand expand in length when inflated.
 18. The surgical instrumentpositioning system of claim 15 further comprising valving means forselectively inflating a number of the inflatable elements.
 19. Thesurgical instrument positioning system of claim 18 wherein the controlmechanism emits control signals to control the valving means.
 20. Thesurgical instrument positioning system of claim 19 wherein the controlsignals are transmitted by electrical wire, optical fiber, or radiowaves.